Linker is all about joint penalty and hangmans, thats all its really about. The buff share ability is usualy more detramental than helpful, since the buff cap limit means everyones little self buff will be given to everyone else and you end up with no room for actual good buffs as they get overwritten annoyingly. The stat share ability in c3 is kind of neat, but most people have similar stat builds anyway so its very little bonus.
Basically, you go linker 3 for the same reason you go linker2, additional links in joint penalty.
And 3 compared to 2 is similar to 2 compared to 1, more links = more useful later on in dungeons. The reason linker is not liked that much in ET is basically because cryo is better then, since frost tree doesnt have a restriction, and ET is just so crowded with mob that linker, even linker2, cant get them all. Linker3 wouldnt either, however theoretically if someone was taking a cryo3, and they just happened to also be a linker, nobody would complain about it i dont think, though cryo3-chrono3 is the standard support slot wizard for ET.
Sorc is strangley good in GVG i hear, but i dont have experience there. And it might have been a cryo3-sorc2 build they were talking about…
cryo is good in pvp for two things, the tree and the shield, maybe cryo2-linker2-sorc2 would turn out ok. Then you can have cryo2s shield, and linker2-sorc2 for good reliable damage output. THen when rank 8 comes around you could grab cryo3 to complete the build and pick up tree and buff your cryo shield further. This would probably be a potent gvg build come to think of it. You would want to go con heavy and be like a tank mage with annoying hard to deal with damage, and massive cc ability.
Yeah… i cant really recommend it because i have no experience with that kind of thing, but cryo2-linker2-sorc2 is a build that i would see in game and think “that person probably knows what they are doing”, because while its not meta, i can see the logic behind it, and if someone were to say they are planning on cryo3 at rank8, it wouldnt sound like a stupid thing.
ID say pick up sorc and get sorc2 and see how you feel about it when rank 7 comes along. You can stick with your plan and go warlock for a more pve oriented build, or you can go cryo2 in preparation for rank 8 and cryo3, and in the mean time, though cryo2 is not so great, at least you will have rank 5 in the shield, which will let you get some pvp functionality out of it, though keep in mind everything ive heard says this sort of build is more gvg/larger scale pvp focused than the 2v2 stuff you see